Hi All, 

After getting my 280Z running after a fresh rebuild, I have fixed the smokey burnt oil from a valve seat , however it is still running ultra rich. To the point where after a new set of spark plugs it sounds great, then after 3 minutes of running they look like the photo below. 

What are some of the ways I can Lean out the mixture to get her running spot on???

Hopefully the video link below will give you guys an idea of the engine condition etc. 

Any help would be greatly appreciated. Thanks in advance!

JD

 

 

 

Usual cause is wiring to water temp sensor in thermostat housing. If the wire is mixed up with another or disconnected, too much fuel is the usual outcome.

Thanks! 

Wires 13, & 49? I will check this afternoon. Is there anyway of checking/by passing this to see if its the sensor playing up? Or perhaps the wiring?

Thanks

I agree with Philip,  the coolant temp connector and thermotime connector are the same and likely plugged into the wrong sensor. 

Just reverse them and see if the rich condition is corrected.

Sounds great. 

Even if you find that the connections are right, measure resistance at the ECU connector to confirm proper function.  Compare the values to the temperature chart in the FSM, or CO's chart which is on the site somewhere.  And clean all of the connections in the harness.  There are two bullet connectors along the fuel rail that could be corroded.

Another fairly common, difficult to diagnose, problem is a hole in the FPR diaphragm.  remove the vacuum line to the FPR and see if it has raw fuel in it.  It should be dry.

btw you do not need to buy new plugs, just clean those with carb cleaner and re-install.  If they re-carbon, continue cleaning and trying to resolve the problem.

Once you get the over-fuel sorted, the plugs will clean themselves.

One more thing - make sure that somebody didn't install turbo injectors or some other high flow injector.  You never know.

What is that God awful sound coming from the engine? Sounds like something coming in contact with the fan blade or an improperly fitting distributor rotor? Doesn't anyone else here this?

Sounded like normal valve lash noise on my computer.

Wouldn't hurt to confirm valve lash since the head had been worked on.  Maybe they're loose.

I've never heard a valve lash noise that loud before. Maybe my computer speakers are sensitive?  

Edited May 24, 20186 yr by rcb280z

Could be the recording device.  Might be your speakers.  I have a Boston Acoustic system with tweeters and separate bass with its own amp.  Circa 1995 Gateway.  Very nice sound.

2 hours ago, rcb280z said:

What is that God awful sound coming from the engine? Sounds like something coming in contact with the fan blade or an improperly fitting distributor rotor? Doesn't anyone else here this?

Motorhead?

RIP Lemmy.

Edited May 24, 20186 yr by siteunseen